140 



WEED FLORA OF IOWA 



Fig. 79-A. Distribution of Crowfoot. 



Distribution. — Common everywhere in Iowa in waste places 

 along roadsides and in fields, occasionally eastward to Newfound- 

 land, south to Florida and north to Manitoba, also in the Rocky 

 mountains. 



Extermination. — This weed is easily exterminated by cultivation. 



Swamp Buttercup (Ranunculus septentrionalis Poir.). 



Description. — A branching, prostrate, smooth or sometimes pubes- 

 cent perennial with multiple fibrous roots, frequently rooting at 

 the nodes and often forming long runners; leaves large, petioled, 

 3-divided, divisions mostly cuneate, petals obovate, larger than the 

 spreading calyx ; achenes flat, strongly margined, pointed by a stout 

 straight beak. 



Distribution. — Common in fields, especially low grounds from 

 eastern Canada to Manitoba ; south to Kansas and Kentucky. Com- 

 mon everywhere in Iowa in low places in Story, Boone, Marshall, 

 Polk, Linn, Clinton, Buchanan, Emmet, Worth, Woodbury, Potta- 

 wattamie, Plymouth, Kossuth, Dallas and Allamakee counties. 



Extermination. — Drainage of the soil and thorough cultivation 

 will soon exterminate this weed. 



